52 FORMS OF MENTAL DEFECT AND DERANGEMENT. 



melancholy temperament or disposition, as habitually and 

 naturally sad or morose. Thus the loris and certain 

 monkeys bear such a character (Cassell and Baird), and the 

 orang (Huxley). The probability, however, is that the ani- 

 mals so described have all been menagerie captives, and that 

 this supposed natural melancholy was, on the contrary, 

 morbid, and the result of confinement and the artificial, un- 

 healthy conditions incident thereto. 



The morbid impulse most usually developed in the course 

 or as the result of melancholia is not the murder of other 

 animals or of man, the destruction of other lives, but suicide, 

 self-destruction, a subject, however, to which I have devoted 

 a special chapter. Morbid impulse is thus a common charac- 

 teristic both of mania and melancholia usually in the form 

 of destructiveness in both cases ; in the one, however, the 

 destructiveness being active, involving the life and property 

 of others ; in the other rather passive, leading to the sacrifice 

 not necessarily intentional or deliberate of the animal's 

 own life. In both classes of cases, however, the morbid pro- 

 pensity occupies a secondary importance, as regards, at least, 

 sequence, to the mental excitement or depression. 



But there is a third group of mental disorders in which 

 the development of certain morbid propensities is a more 

 marked feature than either mental excitement or depression, 

 in which, indeed, neither excitement nor depression may be 

 present, or at least apparent ; in which, in other words, mor- 

 bid impulse is the primary condition in the sense that it is 

 at least the most prominent and important one. In man 

 the most familiar members of the group in question are 



1. -Erotomania, or sexual insanity. 



2. -Kleptomania, or theftuous insanity ; and 



3. Dipsomania, or drinking insanity. 



All these kinds of insanity occur in one form or other 

 among the lower animals. 



.Erotomania occurs, as in man, in the double form of 

 satyriasis in the male, and nymphomania in the female. It 

 would appear to be most common in female animals, especially 

 the mare, cow, bitch and cat. Sometimes nymphomania is 

 spoken of under the term uterine furor ; or this periodical 



